You should have a federal employer identification number (EIN) if you are a sole proprietor and you pay wages to one or more employees. To get one, you must file federal Form SS-4, Application for Employer Identification Number, with the Internal Revenue Service (IRS). If possible file four weeks before you will need the number.
If your business is a partnership or a corporation, you will need a federal EIN even if you are not an employer. You will also need one if your business requires you to file excise, alcohol, tobacco, firearms or employment tax returns. When you register in New York State to collect sales tax, the Certificate of Registration asks for it. Certain nonprofit organizations (churches, clubs, etc.), trusts and estate must also use it.
If you become the new owner of an existing business that you will operate as a sole proprietorship, you cannot use the EIN of the former owner. You must apply for and acquire a new EIN. For application forms and more information about who needs an EIN, contact your local IRS office.
If you are not required to have a federal EIN for your new business, the Tax Department will assign you an account number to be used on all of your business tax records.